between the 0° and -15°9 isotherms, and that hence scavenging of bomb debris —
happens only beneath the -15° 4sotherm,
This assumption coupled with
information on the oloud height and the height of the -15° 4sotherm (about
21,000 feet in summer, 15,000 feet in winter) gives the fraction of the
cloud scavenged by rain,
Knowledge is available on the altitude reached by
the top of the cloud as a function of yield of burst.
Unfortunately the
altitude reached by the cloud bottom has not usually been reported,
Eddy
diffusion theory indicates that the vertical increase of cloud size is
proportional to (time)1/2,
It was assumed, on the basis of AFOAT sniffing,
that the lateral growth is at the rate of three knots.
Dr. Kellogg displayed sample calculations of dose rate versus time
after shot that rainfall occurred.
At low yields the contamination shows
an initial decrease with yield because of the higher cloud rise,
It was
concluded that in a thunderstorm there would not be much rain-out because
the updrafts push the cloud above the region through which the rain falls,
There are virtually no data available with which to test the prediction:
One report on rain-out in the Salt Lake City area indicated a contamination
of less than one percent of the maximum which would have been predicted,
Dr. Kellogg emphasized the incompleteness of the present treatment of
the problem and the severe inadequacy of the available data,
there were gaps in the present picture with respect to:
He said that
local hot spots,
diffusion, and dependence of cloud height on yield, especially at higher
yields.
(The predicted height for the Mike cloud was 80,000 feet; the
observed height was 120,000 feet.)
Our own tests have been carried out
under carefully selected weather conditions.
It is hoped to arrive ata
more logical picture of the effects of different weather conditions,
DOE ARCHTVRS ‘-..<<
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